From mboxrd@z Thu Jan 1 00:00:00 1970 From: David C Niemi Subject: Re: [PATCH] cpufreq: Add documentation for sampling_down_factor Date: Tue, 25 Jan 2011 09:03:40 -0500 Message-ID: <4D3ED83C.4030707@verisign.com> References: <1295951583-19997-1-git-send-email-vishwanath.bs@ti.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1295951583-19997-1-git-send-email-vishwanath.bs@ti.com> Sender: cpufreq-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Vishwanath BS Cc: cpufreq@vger.kernel.org, patches@linaro.org Thanks for taking this on. I wrote this when talking about the patch as a proposed change, now that it is the status quo, I think the second sentence needs to be adjusted a bit as follows: "Set it to 1 it makes no changes from existing behavior," -> "When set to 1 (the default) decisions to reevaluate load are made at the same interval regardless of current clock speed;" DCN Vishwanath BS wrote: > Update cpufreq governor documentation for sampling_down_factor tunable > parameter. > > Signed-off-by: Vishwanath BS > --- > Documentation/cpu-freq/governors.txt | 10 ++++++++++ > 1 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt > index 737988f..ef570ff > --- a/Documentation/cpu-freq/governors.txt > +++ b/Documentation/cpu-freq/governors.txt > @@ -158,6 +158,16 @@ intensive calculation on your laptop that you do not care how long it > takes to complete as you can 'nice' it and prevent it from taking part > in the deciding process of whether to increase your CPU frequency. > > +sampling_down_factor: this parameter controls the rate at which the > +kernel makes a decision on when to decrease the frequency while running > +at top speed. Set to 1 it makes no changes from existing behavior, > +but set to greater than 1 (e.g. 100) it acts as a multiplier for the > +scheduling interval for reevaluating load when the CPU is at its top > +speed due to high load. This improves performance by reducing the overhead > +of load evaluation and helping the CPU stay at its top speed when truly > +busy, rather than shifting back and forth in speed. This tunable has no > +effect on behavior at lower speeds/lower CPU loads. > + > > 2.5 Conservative > ---------------- >